An image forming apparatus employing a backside C-shaped path system or an S-shaped path system includes a first paper exit tray and a first paper exit port. The first paper exit tray is located at an upper surface of the image forming apparatus. The first paper exit port is formed in an inner side surface behind the first paper exit tray. Paper on which an image has been formed is ejected onto the first paper exit tray from the first paper exit port (Patent Literature 1).
In a configuration in which a post-printing processing device (for example, a stapling device) is added to such an image forming apparatus, the image forming apparatus has a second paper exit port. The second paper exit port is located in a rear part of the upper surface of the image forming apparatus. The post-printing processing device is located above the image forming apparatus. The post-printing processing device includes a paper inlet port, a third paper exit port, and a second paper exit tray. The paper inlet port is formed in a rear part of a lower surface of the post-printing processing device (i.e., at a position corresponding to the second paper exit port). The third paper exit port and the second paper exit tray are located at the front of the post-printing processing device.
The post-printing processing device conveys paper ejected from the second paper exit port into the post-printing processing device via the paper inlet port. The post-printing processing device then conveys the paper forward. After post-printing processing, the post-printing processing device further conveys the paper forward to eject the paper to the outside from the third paper exit port. As a result, the paper subjected to the post-printing processing is ejected onto the second paper exit tray.
An in-body space from which paper ejected onto the first paper exit tray is taken out is defined between the image forming apparatus and the post-printing processing device. An opening to the in-body space is located at the front of the image forming apparatus.